This Slow Cooker French Onion Soup is such an easy and delicious recipe! A classic French Onion Soup prepared in the crockpot and loaded with incredible flavor, caramelized onions, and CHEESE!
Flavorful Crockpot French Onion Soup Recipe
This fantastic Slow Cooker French Onion Soup makes a hearty meal and it’s SO easy to make, especially since the slow cooker/crock pot does all the work! Start the soup the night before and come home to a ready-made dinner.
Friends, I have been updating my older recipes on Diethood, and my photos, for the past 3 months like it’s nobody’s business, and this Slow Cooker French Onion Soup finally got to see its new and improved version since its time when I first introduced it to you in November of 2012! Can’t believe I’ve been at this food blog shenanigans for like, 6 years. WOOOT! HIGH FIVES, please!
Okay, so, anyhow!
SLOW COOKER FRENCH ONION SOUP! Baby, YESSS! This stuff is so, so fantastic. I can’t even. I can only advise you to make it right away just to see what the delicious fuss is all about.
There are TWO WAYS to making this French Onion Soup; I will show you both ways:
- First, we can make it all in the crock pot, from beginning to end, and that will take a good 12 hours.
- Secondly, we can partially make it on the stove top and finish it off in the slow cooker.
It’s up to you as to how you want to make it.
HOW TO MAKE FRENCH ONION SOUP IN THE SLOW COOKER
- You are going to grab 6 large onions and slice them… get ready for some real tears, but it’s all worth it, I promise. Sweet onions are best for this soup, but you can also use yellow onions, if that is all you have on hand.
- Transfer sliced onions to the slow cooker, add in melted butter, salt, pepper, and a bit of sugar. If using yellow onions, I advise to add about a teaspoon of sugar. If using sweet onions, 1/4 teaspoon is all you will need.
- Next, you are going to set the slow cooker on LOW and let it cook for like 8 hours, or until onions are browned and caramelized, just as you see them in that photo above. When I make this soup, I always start to prepare it around 10 pm, and then in the morning I just add the rest of the ingredients and finish it up in 4 hours.
- Right before serving, slice up a baguette, ladle soup into ovenproof bowls, place one slice of bread inside each bowl, sprinkle shredded gruyere cheese over the bread and soup, and broil for a couple minutes or until cheese is melted.
You can also make a quicker version of this soup by starting it off on the stove top:
- Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized.
- Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW.
- When soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for couple minutes, or until cheese is melted.
This soup is mostly served as a starter, but considering how good it is, I could make a meal out of it. Bring on the bread and cheese!
MORE SOUP RECIPES:
- Instant Pot Creamy Chicken Tortellini Soup
- Easy Soba Noodle Soup
- Broccoli Cheese Soup (Panera Copycat)
- Stuffed Pepper Soup
- Roasted Tomato Soup
ENJOY!
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TOOLS AND INGREDIENTS USED IN THIS RECIPE
Slow Cooker French Onion Soup
Ingredients
- 6 sweet onions, thinly sliced (you can also use yellow onions, but up the sugar to 1 teaspoon)
- 4 tablespoons unsalted butter, melted
- 1/4 teaspoon sugar
- 1/2 teaspoon salt
- 1/2 teaspoon fresh ground pepper
- 4 to 6 sprigs fresh thyme
- 1 bay leaf
- 6 cups fat free, low sodium beef broth
- 1/2 cup dry white wine
- salt and pepper, to taste
- 6 slices french bread optional
- 1 1/2 cups shredded gruyere cheese, optional (if you can't find gruyere, use swiss cheese)
Instructions
- Place sliced onions in a 6 quart slow cooker.
- Stir in melted butter, sugar, salt, and pepper.
- Top with thyme and bay leaf, COVER and cook on LOW for about 8 hours, or until onions are browned and caramelized. Stir half way through.
- Once onions are caramelized, stir in the beef broth and wine.
- Taste for salt and pepper and season accordingly.
- Cover and cook on LOW for 4 hours, or on HIGH for 2 hours, or until heated through.
- Remove and discard thyme and bay leaf.
- Turn the oven-broiler on High.
- Ladle soup into ovenproof bowls.
- Top the bowls with a slice of french bread and cheese.
- Broil in oven until cheese is melted, about 2 to 3 minutes.
- Serve.
- Please see my notes for a lighter version of this soup, as well as a quicker cooking version.
Notes
- Combine onions, butter, sugar, salt, and pepper in a large skillet, and cook the onions for about 25 minutes, or until browned and caramelized.
- Transfer the onions to the slow cooker, add in beef broth, wine, thyme, salt, and pepper, and cook for 6 hours on LOW.
- When soup is ready, ladle it into ovenproof bowls, place a slice of baguette in each bowl, top with shredded cheese, and broil for couple minutes, or until cheese is melted.
Nutritional info is an estimate and provided as courtesy. Values may vary according to the ingredients and tools used. Please use your preferred nutritional calculator for more detailed info.
30 Min
Freezer Friendly
Low Carb
Instant Pot
Gluten Free
Keto
Chicken
Beef
This was so good! I threw in some leftover pulled pork that I needed to use up. So good! It would have been good without it too! Thanks for the recipe!
I am very glad you enjoyed it! Thank YOU! 🙂
Love how easy this is to make in the slow cooker! Such a hearty and filling comfort food dinner for the family!
I made this using my own stock it is delicious !!!
My husband will go crazy for this onion soup!
Craving this for dinner! Looks great!
It’s rainy and cold here and I am totally craving a big bowl of this soup! Sounds absolutely amazing!
My husband loves this soup and always orders it when we go out. Can’t wait to make this at home for him!
This soup looks so amazing!
Hi! How can i substitute wine? Can’t use it for muslim 🙁
Hi Kate!
You can use apple juice and a tablespoon of lemon juice. I hope that helps! Have a great day!
Anyone tried freezing this soup?
No, I’ve never tried freezing it. I know it stays good in the fridge for a couple of days.
Just an idea…I am making the soup as I type! I used a vegetable slicer for the onions, no tears! Also another tip is breath through your mouth not your nose, it works! 🙂 thanks for the yummy recipe!
Thanks SO much, Audra, for sharing those tips! Believe me when I say that I will be using them asap – I hate the whole onions/crying thing. 😀
Hope you enjoy the soup!!
♥ Kate
Great tips!! Thanks, Audra!
Did you enjoy the soup?
One of my husbands all time favorite soups – gorgeous!
We need some of this soup and Sandra’s onion tea (I’ve heard of that before) for my kiddos too. This is one of my favorite soups. Yours looks fantastic!
Hope your little one feels better soon! I had a sick household yesterday {hubby & both kids}, so I made them a big batch of tomato soup. French Onion is one of my favorites & this looks divine!!
Yup your granny is right , onions are full of vitamins C and I make tea for my kids when they are sick with onion..I know sounds disgusting but with some honey and lemon you could never tell it is with onions(w/peel). I hope your kiddos feel better soon! :*
Your onion Soup looks fantastic, loving your presentation and recipe is tasty too!
I just love the idea of making this in the slow cooker! One of my favorite soups.
I hope the little one is feeling better and that it’s not spreading around the house. 🙁 Today is a day of coincidences I think. I’m catching up on blog reading tonight and the last post I read was also for French onion soup – which I’ve never had. And even more coincidental, I saw it on a menu this morning and decided I need to try it. I’m loving this slow cooker version – my kind of meal! 🙂
This is a great idea that I’ve got to try. My brother once showed up with a scuba mask to chop onions. It seemed to work well for him.
That is hilarious! Lol!
My all time favorite soup….besides corn chowder….is French onion soup!!!! I love your recipe:-) My grandfather makes homemade onion soup that is truly to die for:-) I hope your babies are feeling better, Hugs, Terra
Oh! I hope your lumpy feels better soon 🙁 That’s always a terrible thing to have to see.
Do love this soup though! Winter is fast approaching in Cayman with temps dropping into GASP the 70s! Believe it or not, that totally calls for slow cookers. Bookmarking this bad boy!
I love you made this in a slow cooker! Yum. I could seriously eat an entire pot of this soup alone…
I think I love your idea of changing the beef broth to chicken. I prefer chicken flavor and I will definitely give this recipe and cooking method a try. Onions are very healthy…. and I love them. 🙂
I hope your sweet baby gets well quickly… I know it’s emotionally and physically tolling for parents when they are sick. My kids have coughs now and I wish I could magically get them better.
Have a good weekend. ~ Ramona
My husband and I looooooooooooove French onion soup and we order it when it’s available. We’ve made once at home but it’s been a while. I don’t own a slow cooker but maybe I can cook slowly on a cast iron? Looks so delicious!